Page 565 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 45: Airway Management 385

INDICATIONS FOR INTUBATION TABLE 45-2 Indications for Converting Noninvasive Ventilation to Intubation

The decision about whether to intubate a critically ill patient requires and Mechanical Ventilation
that a practitioner at the bedside synthesize all of the information they Patient inability to tolerate noninvasive ventilation
have at their disposal about a patient, compare it to their institutional Unfavorable anatomy and poor mask fit or large leak
practice patterns and resources, and decide how to proceed. These deci-
sions are rarely clear-cut; reasonable practitioners can arrive at different Progressive hypercapnia in spite of adequate levels of support (typically over 1 hour)
decisions in identical circumstances. Patients who require intubation Requirement for unacceptably high airway pressure (typically total delivered pressures
as part of the initial management of their respiratory failure include >20 cm H O)
2
but are not limited to those with cardiopulmonary arrest, respiratory Hypoxemia in spite of appropriate levels of continuous positive airway pressure and high Fi O 2
arrest, acute respiratory distress syndrome (ARDS) of almost any cause,
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and any patient who is unlikely to respond to noninvasive ventilation Diminished mental status and inability to protect the airway
(Table 45-1). The decision to intubate a patient after noninvasive venti- Respiratory pattern consistent with evolving fatigue or impending respiratory arrest
lation is even more difficult to make. Triggers to convert to an invasive
airway include progressive hypercapnia in spite of adequate levels of ASSESSING THE PATIENT PRIOR TO INTUBATION
support (such as a patient with sleep apnea who is worsening on biphasic
positive airway pressure [BIPAP]), unacceptably high airway pressure All patients being evaluated for tracheal intubation should be treated with
on noninvasive ventilation, hypoxemia that persists in spite of moderate the highest Fi O 2 available. Oxygen saturation, blood pressure, heart rate,
levels of continuous positive airway pressure (CPAP) and high fraction electrocardiography (ECG), and the frequency and strength of respiration
), diminishing mental status, patterns of respi- should be closely monitored. Blood gas analysis may be helpful in facilitat-
of inspired oxygen (Fi O 2
ration that suggest evolving respiratory muscle fatigue or impending ing the decision to intubate the patient, but has been largely supplanted by
respiratory arrest, and unfavorable anatomy (which is present at the start pulse oximetry, which is also essential for monitoring during intubation.
of treatment, or which evolves) (Table 45-2). Patients requiring urgent intubation benefit from an expeditious
In patients with airway compromise, two decisions need to be made but thorough assessment of their underlying medical conditions and
at the time the patient is evaluated: (1) Does this patient require an airway anatomy (Tables 45-3 and 45-4). The possibility of increased
artificial airway? and (2) Does this patient require a tracheostomy? It
may be difficult or impossible to translaryngeally intubate the trachea
in patients with an unstable cervical spine, airway tumor, unfavorable TABLE 45-3 Medical Evaluation for Intubation
anatomy, or significant facial trauma. Preparation for tracheostomy Neurologic factors
should occur concurrently with preparation for translaryngeal tracheal Elevated intracranial pressure
intubation in such high-risk patients. Presence of intracranial bleeding, arteriovenous malformation, or aneurysm
The decision to intubate patients in cardiopulmonary arrest is a simple
one, as intubation is the safest and most effective way to both ensure Cervical spine disease
adequate ventilation in these patients and to protect their airway. The Cardiovascular factors
goal of intubating the trachea in the patient in shock is to decrease Ischemia
the proportion of cardiac output devoted to perfusing respiratory Hypovolemia
muscles, allowing this blood flow to be diverted to other vital organs.
Myocardial infarction (especially within the past 6 months)
Cardiomyopathy
TABLE 45-1 Indications for Tracheal Intubation Dysrhythmias
Airway support Drug allergies
Diminished mental status or decreased ability to maintain airway and clear secretions Pulmonary factors
Compromised airway anatomy Severity of hypoxemia, airway obstruction, or lung restriction
Aspiration risk
Diminished airway reflexes, full stomach, or fluctuating consciousness
Nothing by mouth (NPO) status
Requirement for sedation where airway control may be difficult to establish
Morbid obesity
Pharyngeal instability
Impaired gastric emptying or gastroparesis
Pulmonary disease
Ileus
Acute respiratory distress syndrome
Obstruction
High-pressure pulmonary edema unlikely to respond to noninvasive ventilation, or Pregnancy
which has not responded to a reasonable trial of noninvasive ventilation
Coagulation factors
Hypoventilation (including central nervous system causes and weakness)
Thrombocytopenia
Hypercapneic respiratory failure that has failed noninvasive ventilation
Anticoagulant therapy
Failed trial of extubation
Coagulopathy
Forseeable protracted course of respiratory failure Recent or anticipated therapy with thrombolytics
Circulatory Contraindications to succinylcholine
Cardiopulmonary arrest Major burn within the past year
Shock Crush injuries
Other situations Stroke or spinal cord injury resulting in denervation of a significant portion of the body
Elevated intracranial pressure requiring hyperventilation (increasingly rare) Malignant hyperthermia
Transport to less monitored situations Hyperkalemia

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